Telephone system



Aug. 6, 1929. w. G-REEN 1,723,153

TELEPHONE SYSTEM Filed June 20, 1928 INVENTOR Z 1 1. Gwen ATTORNEYtiihilTED STATES Patented Aug.

Application file-:1 June 29, 1323.

This invention relates to telephone systems, and more particularly totelephone metering systems in which the subscriber is charged for thenumber of calls made or completed, or for the length of each call, orfor both the number of calls made and for the length of each call.

It is an object of this invention to provide a novel system in which thesubscriber is accurately charged for the actual use of his telephonefacilities, without interfering with the etliciency thereof.

In telephone metering systems, a recording meter located either at thesubstation or at the central office may be operated by transmitting overthe circuit direct current impulses of higher voltage than that norms lyin the circuit. The present invention embodies with this method of meteroperation a register bridged from one side of the line to ground, avoltage breakdown valve connected in series withsaid register, means forimpressing on said line directcurr nt impulses of supernormal voltage,and means for modifying the rate of growth of said impulses.

A better understanding of the invention may be had from the detaileddescription hereinafter following. I

The drawing represents (hagrammaticall a telephone circuit illustratingthe invention.

In the drawing there are shown two subscribers stations A and B, withsubscribers loops extending to the central oflice and terminating in thejacks 13 and 13. As shown, A represents the station of the callingsubscriber and B that of the called subscriber. The substations comprisethe usual transmitters 1 and 1, the receivers 2 and 2, the receiverhooks 3 and 3, the contacts 4: and 4, and 5 and 5, respectively, theinduction coils 6 and 6, the ringers 7 and 7, and the condensers 8 and8. In addition, there are located at the substations registers 9 and 9bridged from one side of the line to ground at- 10 and 10 through thereceiver hook contacts 11 and 11 and in series with voltage breakdownvalves 12 and 12. The function or the voltage breakdown valve is toprevent the passage of current of normal line volt age, for example, 24:or 48 volts,irom the line to ground through the relay 44 of the registerwhen the receiver is oil the hook, and to permit the passage of acurrent when an impulse of supernormal voltage, for examensue harem@FFHQE.

GJOB TO AMERICAN L-TKOYQ'T (3 F I EVI YUM-n.

Serial No. 5286,1 55.

pie, 120 volts, is impressed on the line. The Schroter tube, torming thesubject matter of Patent No. 1,605,601, is particularly adaptable foruse as the breakdown voltage valve in this invention.

The cord circuit C of the central otiice is here illustrated as theimpedance coil teed type. Obviously, a cord circuit of the re pea-tingcoil teed type may be used, it deired. The cord circuit shown comprise,the usual current source 14. grounded at 15, the impedance coils 16, 16,17 and 17, the capacities 18 and 18, the supervisory relay l9 and thecord conductors 20, 20, 21 and 21. The impedance coils 16 and 1? areconnected to the source 14 through the armatures 22 and 22 and thecontacts 23 and 23, respectively. Adapted to be bridged across the cordcircuit to ground at 26 is a means 2% (shown in the drawing below thedotted line 25) tor impressing on the line direct current impulses ofsupernormal voltage, for example, 120 volts. This means com rises thedirect current source 27 of higher voltage than that of the linebattery, the commutator 28 and the connecting loads 29 and 29. Anauxiliary direct current source 30 of line battery voltage is connectedin series with the connecting leads 29 and 29. A switching mechanism 31is associated with the cord circuit to disconnect the source l i fromthe calling subscribefis line and to con ncct thereto th auxiliarysource 30. This switching mechanism comprises the relay 32 connected toground atthe armatures 22 and 22, the conductor 3%, the a ture 35, thecontact 36 and source 37 connected to ground at 38. The supervisoryrelay 19 when energized attracts its armature which establishes aconnection with the con tact 36. The establishment of this connectioncloses the circuit of the relay 32 and causes its energization. henenergized, this relay attracts its armatures 2 and 22 to break theirconnection with contacts 23 and 23, respectively, and to establish theirconnection with contacts 39 and 39, rcspeo tively. The latter stepcompletes the association of the auxiliary source 30 with the callingsubscribers line in place of the source 1 1. The auxiliary source 30 isgrounded at 40 through the commutator 28. As shown, the commutator 28has an insulated segment 41 to which is connected one terminal of thesource 27. At predetermined intervals of time, the rotation of thecommutator under the influence of clock mechanism or driving means, notshown, removes the ground 4.0 from the circuit and momentarily connectsthe current source 27 in the circuit through the segment 41. The removalof the ground 40 from the circuit, when the current source 27 isconnected therein, prevents the impulses of relatively higher voltage,generated by the source, from being by-passed to ground. It should beunderstood that the representation of the commutator shown is merelydiagrammatic. Other means may be used to accomplish the same purpose.Choke coils 42 are connected in series with the connecting leads 29 and29 to modify the rate of growth of the impulses impressed by the source27 through the commutator 28. Also, a capacity 43 is connected betweenthe connecting leads 29 and 29. The choke coils and the high capacitytogether serve to prevent any objectionable disturbances in the talkingcircuit, due to the high voltage impulses impressed on the line.

In the drawing, a telephone system is illustr ted in which the callingsubscriber is charged with the length of time his instrument is used forconversational purposes. However, it is to be understood that thisinvention may be embodied in syste .s in which the subscriber is chargedfor the number of calls made or for both the ninnber of calls made andthe length of each call, or in which the charge is made on the multiplebasis.

The operation of the system is as follows: lVhen the calling subscriberat station A removes his receiver from its hook to initiate a call, aconnection is established to the central otiice in the well-knownmanner. At this time, a current of normal line voltage is flowingthrough the substation circuit. The removal of the receiver alsoestablishes a connection from the line through the receiver hook 3 andthe Contact 11 to the voltage breakdown valve 12, thus bridging thelatter from the line to ground. However, no current flows through therelay l i of the register, due to the fact that the voltage breakdowntube does not permit the passage therethrough of current of such lowvoltage as that normally impressed on the line. After the connection.has been completed through the cord circuit C to the station B of thecalled subscriber, and when the called subscriber removes his receiverfrom the hook, the circuit including the supervisory relay 19 is closedin the manner well known to those familiar with the art. The closure ofthis circuit and the resulting energization of the supervisory relay 19causes the latter to attract its armature which establishes a connectionwith the contact 36. The establishment of this connection closes acircuit of the relay 32, constituting a part battery switching mechanism31. 1e energization of this relay causes the l to be disconnected fromthe calling suoscribers line and the auxiliary battery 30 to besubstituted therefor in the manner described above. At predeterminedintervals of time, for example, every fifteen seconds, the commutator 28under the control of clock mechanism or driving means, not shown,disconnects the ground from the circuit and momentarily connects thedirect current source 27 in the circuit through the segment ll wherebyan impulse of relatively high voltage, for example, 120 volts, isimpressed on the calling line. This impulse of relatively high voltagecauses the valve 12 to break down and permit the flow of current acrossits terminals through the relay let of the register 9 to ground 10. (Thevalve 12 may be designed so that it will absorb a part of the voltage,thus serving also as a reducin valve to permit only a reduced current toflow herethrough to the relay of the register.) This current energizesthe relay of the register which attracts its armature and advances thecounter-mechanism one step. As stated above, these impulses areimpressed periodically on the line to register permanently in suitableunits the length of each conversation. The circuit traversed by thesecurrent impulses includes the round 26, the source 27, the segment ii ofthe commutator 28, the choke coils 42, the connecting leads 29 and 29,the cord conu 1 LA. (.tLlCLLiLS 20 and 21, the jack 13, both sides ofthe calling subscribers line through the substation circuit to thecontact 11, the voltage breakdown valve 12, the relay let of register 9to ground at 10. lVhen the receiver are returned to the hooks, theregister, as well as the impulse impressing means, is removed from thecircuit.

As shown and described, the impulse im pressing means is connected onone side of the cord circuit only, since, in general, ii-i is desirableto charge the call to the calling subscriber only. It is obvious,however, that the same mechanism could bev applied on the other side ofthe cord circuit or on both sides of the cord circuit, if desired. Theimpulse impressing means, indie ted in the drawing below the dotted line2o25, may be common to all the cords the given exchange or to a group ofcords or, if desired, may be supplied for each cord separately.Likewise, said impulse impress'ug means may be associated with the cordcircuit throi 7 other means in such a manner that the operation of themeter will begin at any desired time during the connection.

While this invention has been illustrated in connection with a typicalcord circuit using manual operation, it is apparent that it is equallyapplicable to machine switching apparatus.

What claimed is: 1. In combination, a plurality oi --cr1b.ers lines,means tor establ shing iections between two of lines, r

sub

-con asterig means connected from said lines round, means connected inseries with said registering means for preventin the pa. 'agetherethrough of current of normal voltage and for permitting the passagethere through of current of supernormal voltage, a current source tnormal voltage adapted to supply current to said lines, and meansgrounded at one terminal thereof for impressing impulses of supernormalvoltage on said lines to operate said registering means.

2. In a telephone system, subscribers lines, connecting circuits forestablishing talking connections between said lines, metering apparatusbridged from one side of said lines to ground, a voltage breakdown valveconnected in series with said metering apparatus, a current source ofnormal voltage adapted to supply current to said lines, means groundedat one terminal thereof for impressing impulses of supernormal voltageon both sides of said lines in parallel to operate said meteringapparatus, and filtering means located between said impulse impressingmeans and said connecting circuits.

3. In a telep ione system, a calling line and a called line, connectingcircuits for tablishing talking connections between aid lines, measuringapparatus bridged rom one side of said calling line to ground,

voltage breakdown valve connected in series with said measurin apparatusfor preventing the passage therethrough o current of normal voltage and"for permitting the passage therethrougli of current of supcrnormalvoltage, a current source of normal voltage adapted to supply current tosaid lines, a relay adapted to be energized when the circuit of saidcalled line is closer means grounded at one terminal thereof under thecontrol of said relay for pe iodi- Cally impressing impulses ofsupernormal voltage on said calling line to operate said measuringapparatus, and filterin means located between said impulse pressingmeans and said connecting circuits.

4. In a telephone system, a calling line and a called line, connectingcircuits for establi hing talking connections between said lines,registering means bridged across said calling line and connected toground, voltage breakdown means connected in series with saidregistering means for preventing the passage therethrough of current ofnormal voltage and for permitting the passage therethrough of current ofsupernormal voltage, a current source of normal voltage adapted tosupply current to said called line, a second current source of normalvoltage grounded thereof and at one terminal adapted to sunl current-tosaid callin 1. C7

line, a third current source grounded at one terminal thereof andadapted to impress impulses of supernormal voltage on both sides ol saidcalling line in parallel to operate said registering means, and meansadapted to be operated periodically for disconnecting the ground of saidsecond current source and for connecting said third current source tosaid calling line.

5. In a telephone system, a calling line and a called line, connectingcircuits for establishing talking connections between said lines,measuring apparatus connected from said calling line to ground, meansconnected in series with said measuring apparatus for preventing thepassage therethrough of current of normal voltage and for permitting thepassage therethrough of current of supernormal voltage, a current sourceof normal voltage adapted to supply current to said lines, a secondcurrent source of normal voltage, means for disconnecat-ing said callingline from said first current source and for connecting it to said secondcurrent source, and means grounded at one terminal thereof forimpressing impulses of supernormal voltage on both sides of said callingline in parallel to operate said measuring apparatus.

6. In a telephone system, a calling line and a called line, connectingcircuits for establishing talking connections between said lines, ameter bridged from one side of said calling line to ground, a voltagebreakdown valve connected in series with said meter for preventing thepassage therethrough oi current of normal voltage and for permitting thepassage therethrough of current of supernormal voltage, a current sourceof normal voltage adapted to supply current to said lines, a relayadapted to be energized when the circuit of said called line is closed,a second current source of normal voltage grounded at one terminalthereof, filtering means locatec between said second current source andthe connecting circuits, means under the control of said'relay fordisconnecting said calling line from said first current source and forconnecting it to said second current source, a third current sourcegrounded at one terminal thereof and adapted to impress impulses ofsupernormal voltage on both sides of said calling line in parallel tooperate said meter, and means for momentarily and successivelydisconnecting the ground of said second current source and connectingsaid third current source to saic calling line at predeterminedintervals of time.

7. In a telephone system, a calling line and a called line, connectingcircuits for establishing talking connections between the said lines,metering apparatus connected from said calling line to ground, meansconnected in series with said metering apparatus for preventing thepassage therethrough of current of normol voltage and for permitting thepassage therethrough of current of supernormal voltage, a current sourceof normal volt-age common to the connecting circuits, a second currentsource of normal voltage common to the connecting circuits, meansindividual to each connecting circuit for disconnecting said callingline from said first current source and connecting it to said secondcurrent source, and means common 10 to the connecting circuits forimpressing impulses of supernormal voltage on both sides of said callingline in parallel to operate said metering apparatus.

In testimony whereof, I have signed my 15 name to this specificationthis 28th day of May, 1928.

IRVING WV. GREEN.

